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Screw vacuum pumpWith its own advantages of low noise and energy saving, it has become one of the important equipment in the field of machinery manufacturing, automobile and other fields, and plays an active role in improving work efficiency. However, due to many factors, the sealing performance of screw vacuum pump is poor, which directly affects the ability of screw vacuum pump. It is of positive significance to strengthen the research on the factors affecting the sealing performance of screw vacuum pump.

The main reasons for the failure of the sealing performance of the screw vacuum pump:

At present, the screw vacuum pump uses new materials to improve the overall performance of the equipment and extend the service life of the equipment. However, there are many influencing factors for the overall sealing performance of the equipment, which are manifested in the following aspects:

1. The pressure between the rubber bushing and the rotor is too large

In the actual movement process, the rubber bushing and the rotor are in an interference state, and the full use of interference contact can reduce fluid leakage. However, when affected by factors such as the inner wall pressure and the pressure difference between the sealed chambers, the contact pressure is reduced and leakage occurs, thereby reducing the tightness of the equipment.

2. Shear stress of rubber bushing

Under the influence of interference fit, the deformation resistance produces contact stress between the bushing and the sealing position to ensure the seal between the two adjacent chambers. During the operation of the equipment, shear force will be generated between the rotor and the hydraulic pressure. Once the strength of the rubber material is exceeded, the rubber bushing will be torn, resulting in leakage, which is difficult to meet the production requirements.

3. Structural parameters

Fatigue failure is mainly formed under the influence of alternating stress, generally manifested as low stress brittle fracture, and local properties change. After long-term use, the performance of the rubber material changes and the leakage problem occurs, which is difficult to meet the actual work requirements. Therefore, the equipment structure has a direct impact on the equipment sealing.

Effective countermeasures to improve the sealing performance of screw vacuum pump:

1, appropriately increase the amount of interference

Screw pump interference mainly refers to the size of the interference fit between the metal rotor and the stator rubber bushing. In specific work, there must be a certain interference between the stator and the rotor to ensure the sealing between the closed chambers. Because of this, the interference value between the stator and the rotor will greatly affect the performance of the equipment. Generally, under the premise that the series does not change, the size of the interference directly determines the pressure bearing capacity of the chamber and affects the lifting capacity. The data show that the change trend between the z * large contact pressure and the pressure in the chamber is negatively correlated, and the greater the pressure in the chamber, the z * large contact pressure will decrease. The pressure in the same chamber will increase with the increase of interference.

In summary, when other parameters remain unchanged, the choice of screw pump with large interference can improve its overall sealing performance and lifting pressure, thereby expanding its scope of use. At the same time, in the production process, can also actively attract electric screw pump, in the high difficulty of mechanical manufacturing and other work, can avoid fluid flow screw pump reduce its operating efficiency.

2. Choose materials with higher hardness

Hardness is the main influencing factor of material deformation ability, the greater the elastic value, the easier the corresponding material deformation. In general, there is no independent relationship between elastic modulus and hardness in theory, but it can be seen from the experimental data that the elastic modulus will increase with the increase of hardness, which should be taken into account its impact on the sealing performance of the screw pump. For example, the contact pressure of the rubber bushing is inversely proportional to the internal pressure, the greater the former, the smaller the latter, but the trend of the two changes is consistent. In addition, the greater the hardness of the rubber bushing, the position of the z * large contact pressure curve will gradually rise, and the corresponding sealing performance will also be improved. Therefore, the rubber with higher hardness should be selected to make the screw pump stator to improve its sealing performance.

3. Reasonable optimization of screw vacuum pump structure parameters

The sealing of the rubber bushing of the screw pump is mainly affected by the structure, which makes the volume compression deformation and the shape deformation of the collection. In short, the result of the combined action of pressure and pressure difference in the structure. The critical contact pressure and the pressure change law in the sealing chamber of the equal wall thickness screw pump are similar to those of the ordinary screw pump. Generally, in the mechanical analysis of rubber components, rubber is used as an incompressible material to reduce the uncertainty of the research. However, even the small rubber compression will have a certain impact on the overall structure. Therefore, the overall structural parameters of the equipment are bound to have an impact on the overall performance of the equipment. The screw pump system can be optimized reasonably to achieve the goal of improving the sealing performance of the screw pump. Under the background of the information age, we can research and develop a set of software suitable for adjusting the screw pump coefficient and infiltrate it into the whole production process. At the same time, we can also develop a system to supervise the actual operation condition of the screw pump through real-time supervision and control of power parameters, axial force and other factors, and to optimize the parameters of the screw pump with various parameters, thus improving the sealing performance of the equipment.

As a new type of equipment, screw vacuum pump occupies an important position in the development of many fields, and its sealing directly determines its ability.